Positive Semantics of Projections in Venn-Euler Diagrams
Joseph Yossi Gil4, John Howse5 and Elena Tulchinsky4
| (4) |
Department of Computer Science, Technion-Israel Institute of Technology, Technion City, Haifa, 32000, Israel |
| (5) |
School of Computing and Mathematical Sciences, University of Brighton, UK |
Abstract
Venn diagrams and Euler circles have long been used as a means of expressing relationships among sets using visual metaphors
such as “disjointness” and “containment” of topological contours. Although the notation is effective in delivering a clear
visual modeling of set theoretical relationships, it does not scale well. In this work we study “projection contours”, a new
means for presenting sets intersections, which is designed to reduce the clutter in such diagrams. Informally, a projected
contour is a contour which describes a set of elements limited to a certain context. The challenge in introducing this notation
is in producing precise and consistent semantics for the general case, including a diagram comprising several, possibly interacting,
projections, which might even be of the same base set. The semantics investigated here assigns a “positive” meaning to a projection,
i.e., based on the list of contours with which it interacts, where contours disjoint to it do not change its semantics. This
semantics is produced by a novel Gaussian-like elimination process for solving set equations. In dealing with multiple projections
of the same base set, we introduce yet another extension to Venn-Euler diagrams in which the same set can be described by
multiple contours.
Work done in part during a sabbatical stay at the IBM T. J. Watson Research Center
Research was supported by generous funding from the Bar-Nir Bergreen Software Technology Center of Excellence-the Software
Technology Laboratory (STL), at the department of computer science, the Technion
Research was supported by the UK EPSRC grant number GR/M02606
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